Distillation systems are commonly provided for recovering alcohol, solvents and the like and can include a distillation chamber adapted to receive the liquid to be distilled, a heating unit in heat exchanging contact with the liquid in this chamber, a cooling and condensing unit in contact with a vapor phase of liquid from this chamber and means for cooling the latter unit.
Such apparatus can be used, for example, for the distillation of alcohol from alcoholic liquids or mixtures, for the distillation of solvents, e.g. to clean the latter, and for any other purpose in which a vaporizable liquid must be distilled.
For the cleaning (generally degreasing) of metals with solvents, the solvent is highly contaminated by oils, fats and like greasy materials as well as with other contaminants. Economical reuse of such solvents requires their cleaning and purification and industrial methods make use of distillation for this purpose.
Distillation apparatuses for the aforedescribed purposes have heretofore generally utilized heating units which were electrically energized or which received thermal energy from some external source. The cooling unit could be a refrigeration unit which was also driven by electrical energy and which released heat into the surroundings.
With increasing energy shortages and energy costs, such apparatus was not technologically advantageous, nor was it compatible with increasing concern for environmental thermal pollution and energy wastage.